[ExI] lockheed's fusion video

BillK pharos at gmail.com
Wed Oct 22 17:46:47 UTC 2014

On Wed, Oct 22, 2014 at 5:22 PM, spike wrote:
> 4 cm of lead gives 60% chance of absorption, 8 cm takes us to about 86%, 12
> cm to 95%, 16 cm gets us 98% chance of absorption, and that's where I can't
> do these without an envelope or a spreadsheet anymore.  The only reason I
> knew how to do those three is that I memorized a long time ago 1-1/e, 1-e^-2
> and 1-e-3 and 1-e-4: 0.63, 0.86, 0.95 and 0.98, and everything past that is
> over 0.99.  Those numbers have a lot of real-world applications.  Knowing
> just those four numbers gives you lots of opportunities to impress your geek
> friends.

NextBigFuture has another report out which mentions the shielding requirement.

Recent criticism has forced project leader McGuire to provide more
technical and project details.

McGuire acknowledged the need for shielding against neutrons for the
magnet coils positioned inside the reactor vessel. He estimates that
between 80 and 150 centimeters of shielding would be needed, but this
can be accommodated in their compact design. Researchers contacted by
ScienceInsider say that it is difficult to estimate the final size of
the machine without more knowledge of its design. Lockheed has said
its goal is a machine 7 meters across, but some estimates had
suggested that the required shielding would make it considerably


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